Scaling and annealing metals.



APPLIOAIIOI FILED ooT.1o, 1911.

'Patented Dec. 17,1912.

Samnaun osBonN coman-cotas, or wns'rmms'rnn, LONDON, nNoLaNn.

. To oil whom i may concern:

wenste.

scanned AND annulaire nnfrALs.

Spec-invention of Letters Pate-nt.'

Patented m0411912;

application med october 1o, 1911. Qseai, No.- ssasaa Be it known that l, Sminannl OsoR'N CowPnR-Conns, a subject of the King of Great Britain, residing at 82 V'ictoriastreet, Westminster, London, England, have invented new and useful mprovements in Scaling and Annealin Metals, of which the following isa speci cation.

My invention relates to improvementsin the existing methods of scaling and anneal ing metals, which metals .may be` Subsequently coated with other metals, enamels, lacquers or thelike, if desired, and to-that class of process described in the specification of former Letters Patent No. 979,931I

' (dated December' 27, 1910), wherein metallic articles to be scaled and annealed are heated in an atmosphere of a reducing gas.

In carrying out such a process as that. de.

scribed in the'sp'eciiication of the aforesaid patent, it is found advantageous to cool the articles rapidly owing to the fact that if i thel articles are cooled slowly a deleterious lm is deposited on the surface of the clean metal. y

As the result of experiment I have discovered that, if, during the scaling and an' nealing operation the metallic articles are inclosed in an envelop that the film herein-4 before referred to is not formed, andmy invention, therefore, consists in incloslng thearticles to be treated in a vessel or envelop which may entirely inclose the articles, so

` that the reducing gases will have to, penetrate the substance of the said vessel or envelop, or may have formed in it openings,

which, while allowing contact of the reducing gases with the metallic articles, for et'- ecting lthe reduction of the scale, do not allow access of the deleterious gases to the said articles on account of the slow'diiusion of such gases when cooling down.

The envelop in which the articles are inclosedv may be of cast or wrought iron, or of unglazed earthenware,.or any other material through which the reducing gases will diiuse at or aboutv the annealing temperature.

It will-*tie understood that when the envelop is formed of met-al, as. for example, wrought iron, the reducing gases diuse through the said envelop when the latter is at a high temperature 1n -a sufficient quantity to reduce the scale and oxid upon the articles within the envelop to the metallic state. When the envelop containing the articles, however, is withdrawn into the coolin chamber the deleterious gases do not di use lthrough the envelop, and when the latter is open are found to penetrate through "the openings only for a relatively short distance, so that by making the envelop of the proper 4dimensions all-the articles contained therein can be kept out of contact with f these gases.

-My inventlon will be readily understood by reference to theaccompanying drawing,

' in which f Figure( 1 Ais a longitudinal section illus-` Itrating a vessel or, envelop made of two metal plates which are unitedat the edges,

and which are represented as inclosing be- -tween them a series of metal platestobe scaled. Fi is a sectional elevation of `a vessel which unglazed earthenware and which is represented as being in two parts, the lower part being formed, with a channel into which the edge of the other part is inserted and sealed by means of sand or other suitable material which forms a pbrous joint through which only .the reducing gases will penetrate. Fig. 3 is a transverse section on the line 3 3, Fig. 2. Fig. 4 is a view somewhat similar to Fig. l, except that the edges of theplates at the ends of the envelops-are represented as being arranged at a short distance apart, so as to leave a restricted opening, it being found in practice, that, owing to the very slow diffusion of the deleterious gases contained in the reducing gases, these deleterious gases do not penetrate the restricted openings to any appreciable extent, while the articles are cooling down. It is found, for example, in practice, that the distance to which the deleterious gases penetrate through -the openings, is roughly four times the smaller dimension of any particular opening; for instance, if the opening be 6 inchessby 1 vinch in cross sect-ion, the dist-ance the deleterious gases would penetrate into the kenvelop would be 4 inches, this being four times the smaller dimension of the opening. It results that if the distance the articles are into the scaling and annealing chamber and may be made of cast iron or of 11o 'velop such as above described are introduced l heated therein to the required temperature,-

`to a metallic state by the reducing ases which penetrate into the vessel elther through the walls thereof, or through the restricted openings which are left, vas in the case of the arrangementshown in Fig. 4 or, as in the arrangement shown in Figs. 2 and 3.

The scaling operation having been com-` pleted the vessel is withdrawn into the cooling chamber, as described in the specification before referred to, and remains there until the temperature falls to about 150 C., the envelop preventing the articles from coming into contact with any gases. which would produce the lilm before referred to.

Claims.

1. A process for removing scale from land annealing metals which consists in inclosing the articles to be treated, in an envelop placing the articles and envelop in the annealing chamber and heating it 1n an atmosphere ofreducing gas which penetrates the substance of the Walls of the envelop, for

thepurpose of scaling the metallic contents thereof, and in then allowing the envelop and its contents to cool in a reducing gas for the purpose of annealing the contents, the deleterious gases during the cooling process being maintained out of contact with the metallic articles by the Walls of the inclosing envelop.

. 2. The process of removing scale from metals, which consists in inclosing the art'lcles to be treated in an envelop, placing sald articles and envelop in an annealing chamber, supplying said chamberpwith reducing gas and heating said chamber, the said envelop permitting said reducing gas to pass into the interior of the sameinto contact with said articles, and preventing thecontact of deleterious gases therewith.

3. The process of removing 'scale from metals and annealingshe same, Iwhich consists in inclosing the articles to be treated in an envelop, placing the articles' and envelop inl an annealing chamber, supplying reducing gas to said chamber and heating said chamber, and then allowing said envelop and its contents to cool in the same conditions, the said envelop permitting the reducing gas to pass into the interior of t-he same and into contact with said articles and preventing the contact of deleterious gases therewith.

JOHN E. BoUsFmLD,

E. DABBs.

COWPER-COLES. 

